I was at a library sale of an old pastor who had passed away and his family was selling his entire library. I bought a copy of a first edition of Murdock'stTranslation of Mosheim's Ecclesiastical History for $.50. I later found out it was worth about $500. Needless to say I still have it.
Sadly with the advent of EBay, many of those great finds are gone.
Estate sales and book stores have gone digital.
I found a book barn in Virginia a few years ago that was full of wonderful books, and selling them for what ever you wanted to give for them.
I limited my take to five select ones and gave him a twenty. As I was walking out I told my wife that we better hurry. Someone might arrest us for robbery. Among those five I found two old Nestle Greek Testaments (1906 [6th ed] and 1952 [21st ed]) and a 23rd addition of the Nestle-Aland Testament.
I've got many books on my library shelves that I haven't read.
It's like a wish list that is ever present. Each year I read a few and add a few. Crabby, here on the board, has offered many great selections.
My digital library is another story... I pick them up for free or when the price is right.... many books unread. ...but there's still time.
Never stop learning.
Rob